Pneumatic shifting force supporting devices of the type mentioned above are particularly used with trucks. They disburden the driver of the respective vehicle by greatly reducing the force that needs to be used at the stick shift when engaging a gear or shifting gears. In practice, a variety of such shifting force supporting devices exist.
Shifting force supporting devices of the type mentioned above have to meet certain requirements which partially conflict with each other's objectives. In addition to the usual demands placed on motor vehicle features (cost-effective, light, compact, high-performance, reliable, low maintenance, durable), there may be specific requirements which are connected to the changing fringe conditions within the same application environment. For example, when engaging different gears in the gearbox, a different amount of force may be necessary. If the goal is for the driver to use mainly the same force on the stick shift when engaging gears, then the power boost would have to be stronger when engaging some gears than when engaging others. Shifting force supporting devices that have so far been proposed to solve this issue are typically structured in an exceedingly complex and elaborate manner. A further problem area is the dynamic requirements of the shifting force supporting device. Not only do different drivers activate the stick shift differently, each driver also expects from the shifting force supporting device optimal support for him or her individually. In addition, different driving situations require different, dynamic shifting procedures. Especially while ascending, a particularly quick gear change is necessary in order to minimize the falling back (loss of speed) of the vehicle during the gear change. Shifting force supporting devices, however, that are construed with especially high shifting dynamics are in danger of overdriving during activation of a stick shift with a lower dynamic which can in turn lead to internal blows or vibrations and/or blows or vibrations to the stick shift.
In light of the afore-described issue, the object of this invention is to supply a shifting force supporting device of the type specified above—when fulfilling the usual demands outlined above—which is characterized by an especially advantageous performance in regards to the dynamic gearbox range under varying operating conditions.